Silicon carbide/graphite composite and articles and assemblies comprising same

Abstract

A silicon carbide-graphite composite is described, including (i) interior bulk graphite material and (ii) exterior silicon carbide matrix material, wherein the interior bulk graphite material and exterior silicon carbide matrix material inter-penetrate one another at an interfacial region therebetween, and wherein graphite is present in inclusions in the exterior silicon carbide matrix material. Such material may be formed by contacting a precursor graphite article with silicon monoxide (SiO) gas under chemical reaction conditions that are effective to convert an exterior portion of the precursor graphite article to a silicon carbide matrix material in which graphite is present in inclusions therein, and wherein the silicon carbide matrix material and interior bulk graphite material interpenetrate one another at an interfacial region therebetween. Such silicon carbide-graphite composite is usefully employed in applications such as implant hard masks in manufacturing solar cells or other optical, optoelectronic, photonic, semiconductor and microelectronic products, as well as in ion implantation system materials, components, and assemblies, such as beam line assemblies, beam steering lenses, ionization chamber liners, beam stops, and ion source chambers.

What is claimed is: 
     
       1. A silicon carbide-graphite composite comprising;
 (i) a first interior region including a bulk graphite material; 
 (ii) a second exterior region including a silicon carbide matrix material defining an exterior of the composite, wherein graphite is present inclusions in the silicon carbide matrix material; and 
 (iii) an interfacial region between the first region including the bulk graphite material and the second region including the silicon carbide matrix material, wherein the bulk graphite material and exterior silicon carbide matrix material inter-penetrate one another at the interfacial region, 
 wherein the composite is devoid of any silicon carbide capping layer. 
 
     
     
       2. The silicon carbide-graphite composite of  claim 1 , wherein each of the (i) interior bulk graphite material and (ii) exterior silicon carbide matrix material has a respective thickness, wherein the thickness of the interior bulk graphite material is greater than the thickness of the exterior silicon carbide matrix material. 
     
     
       3. The silicon carbide-graphite composite of  claim 1 , wherein the exterior silicon carbide matrix material has a thickness in a range of from 150 to 1000 μm. 
     
     
       4. The silicon carbide-graphite composite of  claim 1 , wherein the grain size of graphite in the silicon carbide-graphite composite is in a range of from 5 to 20 μm. 
     
     
       5. The silicon carbide-graphite composite of  claim 1 , wherein the density of the silicon carbide-graphite composite is in a range of from 1.6 to 2.4 g per cc of the composite. 
     
     
       6. The silicon carbide-graphite composite of  claim 1 , wherein coefficient of thermal expansion (CTE) of the composite is in a range of from 4 to 6.5×10 −6 /° C. 
     
     
       7. The silicon carbide-graphite composite of  claim 1 , wherein the composite has a characterization parameter, C p , in a range of from 0.5 to 3.2%/cm −1 , wherein C p  is defined by the relationship:
     C   p   =W   g   /[S/V]   
 
       wherein:
 W g , is the percent (%) weight gain of the graphite material that is subjected to contact with silicon monoxide to effect reaction producing the composite; and 
 S/V is the surface-to-volume ratio of the product composite, wherein S is the surface area of the composite, in square centimeters, and V is the volume of the composite, in cubic centimeters. 
 
     
     
       8. The silicon carbide-graphite composite of  claim 1 , wherein the composite is a vitreous carbon-free composite. 
     
     
       9. The silicon carbide-graphite composite of  claim 1 , wherein the composite contains no free silicon. 
     
     
       10. The silicon carbide-graphite composite of  claim 1 , wherein the composite is doped with nitrogen. 
     
     
       11. The silicon carbide-graphite composite of  claim 1 , wherein the composite is doped with nitrogen at a nitrogen content of from 0.1 to 1.2% by weight, based on total weight of the composite. 
     
     
       12. An article comprising a silicon carbide-graphite composite, the silicon carbide-graphite composite comprising
 (i) a first interior region including a bulk graphite material; 
 (ii) a second exterior region including a silicon carbide matrix material defining an exterior of the composite, wherein graphite is present inclusions in the silicon carbide matrix material; and 
 (iii) an interfacial region between the first region including the bulk graphite material and the second region including the silicon carbide matrix material, wherein the bulk graphite material and exterior silicon carbide matrix material inter-penetrate one another at the interfacial region, 
 wherein the composite is devoid of any silicon carbide capping layer. 
 
     
     
       13. The article of  claim 12 , comprising an implant hard mask. 
     
     
       14. The article of  claim 12 , comprising a susceptor for an LED growth apparatus, wherein the silicon carbide matrix material of the composite is at least a portion of a surface of the susceptor. 
     
     
       15. The article of  claim 14 , wherein the susceptor contains through hole(s) therein, and the silicon carbide matrix material of the composite is at internal surface of the hole(s).